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Mapping local field enhancements at nanostructured metal surfaces by second‐harmonic generation induced in the near field
Author(s) -
CELEBRANO M.,
ZAVELANIROSSI M.,
POLLI D.,
CERULLO G.,
BIAGIONI P.,
FINAZZI M.,
DUÒ L.,
LABARDI M.,
ALLEGRINI M.,
GRAND J.,
ADAM P.M.
Publication year - 2008
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2008.01892.x
Subject(s) - second harmonic generation , femtosecond , materials science , plasmon , optics , polarization (electrochemistry) , near field optics , nonlinear optics , high harmonic generation , surface plasmon , local field , pyramid (geometry) , nanoscopic scale , surface plasmon resonance , near field scanning optical microscope , near and far field , aperture (computer memory) , optoelectronics , nanotechnology , nanoparticle , optical microscope , laser , physics , scanning electron microscope , chemistry , acoustics , condensed matter physics
Summary We report on an aperture scanning near‐field optical microscope in which femtosecond pulses are coupled to a hollow‐pyramid aperture sensor. Such probe displays high throughput and preserves pulse duration and polarization, enabling the achievement of sufficiently high peak power in the near field to perform nonlinear optics on the nanoscale. We use the system to observe the nonlinear optical response of nanostructured metal surfaces with sub‐100‐nm spatial resolution. We study second‐harmonic generation from gold nanoparticles both isolated and in high‐density patterns, highlighting a strong dependence of the generation efficiency on the shape and on the fine structure of the nanoemitter. In particular, we present results on closely packed gold triangles as well as on nanoellipsoids with different local surface plasmon resonances.